Henrietta Cattarina Potgieter (Pieterse) - Same person?

I would say no they aren't.
Check the dates the profiles were created - Henrietta Cattarina Potgieter's profile was created on December 4th, 2015 - which would not tie up with with our profile as she died on 1st July 2018 - three and a half yeas later.
Neither of them are listed on the database as they have been logged on their profiles. There is a possibility that their names names could have been misspelt though..